Floating support fitted with a turret including rolling bearings protected from water

Abstract

An oil production floating support including a disconnectable mooring system for anchor lines to the sea bottom and for bottom-to-surface connection pipes. The floating support comprises a mooring buoy for mooring lines and bottom-to-surface connection pipes, the buoy preferably being an annular buoy. The floating support being characterized in that said turret has a watertight tubular outer structure having a bottom wall assembled in watertight manner to the bottom end of the watertight tubular outer structure. The tubular outer structure contains an inner structure secured at its top end to the hull. The inner and outer tubular structures co-operate with at least one bottom rolling or friction bearing, enabling the inner structure to turn, with the outer structure not being caused to turn when the floating support is caused to turn about a vertical axis ZZ′ of the cavity and of the watertight tubular outer structure. The bottom rolling or friction bearing being situated beneath the surface of the water, but inside said watertight outer structure.

The invention claimed is: 
     
       1. An oil production floating support including a disconnectable mooring system for anchor lines anchored to the sea bottom and for bottom-to-surface connection pipes, the floating support comprising:
 a mooring buoy for said anchor lines and first bottom-to-surface connection pipes extending from said buoy, to which they are moored, down to the bottom of the sea; 
 a turret extending in a through cavity passing along the entire height of the hull of the floating support, said mooring buoy being fastened under the hull of the floating support to said turret, said turret co-operating with the hull within said through cavity passing along the entire height of the hull of the floating support, said turret being rotatably mounted relative to said hull via at least one rolling or friction bearing, so as to allow said floating support to turn about a substantially vertical axis ZZ′ of said turret and of said cavity without causing said mooring buoy to turn relative to the vertical axis ZZ′; and 
 second connection pipes between the top ends of said first bottom-to-surface connection pipes and the deck of the floating support, the second pipes rising within the cavity to a coupling for a plurality of said second pipes, said coupling being secured to the floating support, said coupling being of the rotary joint coupling type and being rotatably mounted so as to allow said floating support to turn without turning said coupling; 
 the turret further comprising: 
 a watertight tubular outer structure about the vertical axis ZZ′, having a bottom wall assembled in watertight manner to the bottom end of said watertight tubular outer structure; 
 said tubular outer structure containing an inner structure coaxial with said tubular outer structure, the top end of said inner structure being secured to the hull; 
 said bottom wall of the watertight outer structure having a plurality of said first connection pipes passing therethrough in leaktight manner, said first connection pipes passing through and supported by said inner structure; 
 said watertight outer structure not being supported by said hull nor being fastened to said hull, and having dimensions that enable it to float naturally in the water in the cavity in said floating support; 
 said inner and outer tubular structures co-operating with at least one bottom rolling or friction bearing, allowing said inner structure to turn, said outer structure being prevented from turning when said floating support is caused to turn about said vertical axis ZZ′ of the cavity and of said watertight tubular outer structure; and 
 said bottom rolling or friction bearing being situated below the surface of the water but inside said watertight outer structure. 
 
     
     
       2. The floating support according to  claim 1 , wherein at least one support bottom rolling bearing interposed between the bottom wall of said watertight tubular outer structure and the bottom end of said inner structure. 
     
     
       3. The floating support according to  claim 1 , wherein:
 at least one bottom guide lateral rolling bearing interposed between the inner side surface of said outer tubular structure and the outer side surface of said inner structure, said bottom lateral guide bearing being situated below the level of the water surface and closer to said bottom wall of said tubular outer structure than to the top end of said tubular outer structure; and 
 at least one top guide lateral rolling bearing interposed between the inner side surface of the outer tubular structure and the outer surface of said inner structure, said bearing being situated closer to the top end of said tubular outer structure than to the bottom of said tubular outer structure. 
 
     
     
       4. The floating support according to  claim 1 , wherein said rolling bearing(s) is/are constituted by rollers or by wheels. 
     
     
       5. The floating support according to  claim 4 , wherein said rollers or wheels are disposed circularly around said inner structure in the annular space between said inner and outer structures. 
     
     
       6. The floating support according to  claim 1 , wherein said outer and inner tubular structures include abutment means and retaining means preventing said outer structure from sinking in the event of sea water accidentally flooding the inside of the outer tubular structure by loss of watertightness, said abutment means and retaining means enabling the outer structure to be retained by said inner structure. 
     
     
       7. The floating support according to  claim 1 , wherein inner structure includes at its top end a top peripheral plate via which said inner structure is secured to the hull of said floating support. 
     
     
       8. The floating support according to  claim 7 , wherein said top plate bears against a step in the top end of said cavity in such a manner that said top plate does not project above the level of the deck of the floating support. 
     
     
       9. The floating support according to  claim 1 , wherein said inner structure contains a carrier structure in the form of a central pillar of circular section that rests on the bottom wall of said tubular outer structure and that extends up to the level of the deck of the floating support, said carrier structure holding said second connection pipes passing through the inner structure in a supported position, and also supporting said rotary joint coupling resting on top of said carrier structure level with the deck of the floating support. 
     
     
       10. The floating support according to  claim 1 , wherein said buoy includes a top tubular wall, of circular section defining a “valve” chamber when the top edge of the tubular top wall of the buoy is pressed against the bottom wall of the turret, said valve chamber containing the top ends of said first connection pipes passing through the bottom wall of said valve chamber, the top ends of said first pipes being fitted with vales and/or with male or female automatic connector portions supported by said bottom wall of the valve chamber, and said buoy including in its bottom portion an annular box constituting a float under the bottom wall of the valve chamber.